#1
Current temperature=0°C
Temperature before 1 hour
[tex]\\ \sf{:}\dashrightarrow 0+3°C=3°C[/tex]
#2
Temperature before 3h
[tex]\\ \sf{:}\dashrightarrow 0+3(3)=0+9=9°C[/tex]
#3
Temperature before 4.5h
[tex]\\ \sf{:}\dashrightarrow 0+4.5(3)=13.5°C[/tex]
